Electrical connectors generally should not be connected or disconnected while the electrical load is turned on. Electrical arcing between the separated contacts of a live electrical connector present a hazard of fire and of burns to the user, and any such arcing tends to reduce the useful life of the connector.
Nevertheless, due to the fallibility of human nature, it remains true that electrical connectors may at times be inadvertently connected or disconnected while the electrical load is turned on. When the electricity is alternating current, arcing is less of a problem, because the sinusoidal nature of the alternating current will cause the voltage to be zero at some point during the electrical contact separation, and any arcing will tend to self-extinguish. However, when the electricity is direct current, the voltage is constant and never zero, and electrical arcing between the separating contacts will be maintained over a substantial range of contact separations, creating a burn hazard for the user and reducing the useful life of the connector.
One approach is to provide a separate, shorter set of contacts within the connector, and configure the connector so that the shorter contacts are engaged after and disengaged before the primary electrical connections. The lack of current across the shorter connection is then used to trigger a separate switching device placed in the primary electrical circuit that shuts off the current in the circuit before the separation of the primary electrical connections. However, adding an additional contact and switching device increases both the bulk and the cost of the system.
Another approach is to include an insulating barrier that covers the leading end of one of the electrical contacts and blocks the direct through-air path between the contacts as the connectors are mated and un-mated. However, in this approach arcing can still occur through an indirect path that by-passes the insulating barrier.
What is needed, therefore, is an electrical connector that suppresses electrical arcing between separated contacts during connection and disconnection, without adding an additional connection and switching device.